COVID-19 in South Korea - and potential implications for us (wherever we are)
(Updated: 2020-03-22 12:35:48)
So, I have been watching the epidemic in China and Korea since the beginning, but it is still not easy to settle into this reality here in the US.
First of all, everyone, STAY HEALTHY and see what YOU can do!
Second, there are many excellent news articles and information sources, but I’m sharing some more questions (see left panel) and data for those who are curious about the situation in Korea specifically. All data are from press release from KCDC - available to the public in both Korean and English. Kudos!
By the way, to understand the Korean context, see below figure from Washington Post.
(Source: Washington Post’s How countries arond the world have tried to contain the coronavirus)
Q 7. How has the mortality changed?
South Korea had the first COVID death on February 19th. As of 2020-03-22, there have been a total of 104, with an overall mortality rate of 1.2% among all cases.
The below graph shows trend of the overall mortality rate (starting from February 21st). The mortality rate (orange bars) initially increased for several days, but, as the number of new cases increased exponentially (see gray bars also Question 2), the mortality rate declined after the first peak. Then, it has increased gradually to the current level. Since South Korea still has been able to continue the trace-test-isolate strategy, it will be important to monitor mortality trends, providing important insight about this epidemic.
(Source: KCDC’s daily press release, and UN World Population Prospects 2019 Revision)By age group, mortality rate among the 70s follow the overall trend shown above: initial decrease and then increase. Mortality among those 80 and above has increased continuously. Mortality rates among those in their 50s and 60s have remained similar over time.
(Source: KCDC’s daily press release, and UN World Population Prospects 2019 Revision)Note: Age-specific mortality data were first released on March, 3rd, and it has been updated daily since March 11th.
Q 6. How is it affecting children?
Compared to other age groups, incidence rates are much lower among those under 20 (See Question 3). There have been 0 deaths reported in these age groups, and mortality rates are also the lowest among all age groups (See Question 4).
Still, new detailed data from Korea CDC give some information about cases among children younger than 18 years of age. As of 2020-03-17, incidence rate by detailed age group is shown below. Older children have higher infection rates.
(Source: KCDC’s daily press release on 2020-03-17, and UN World Population Prospects 2019 Revision)Note: These age groups roughly corresponds with school system age groups in South Korea.
Of course, this is only epidemiologic perspective. Children’s emotional, social, and economic well-being is more complex and difficult to capture yet.
Q 5. How extensive testing has been?
Very aggressive. As of 2020-03-22, a total of 332 thousand people have been tested. There are 51 million people in the country, and 6 in every 1000 people have been test. This is the highest testing rate in the world. Epidemiological investigation of the case No. 31 (who was confirmed on February 18th) prompted immediate and massive testing in Daegu and nation wide.
(Source: KCDC’s daily press release. The number of tests is calculated based on the daily increase in the total number of tests reported.)Q 4. What is mortality - overall and by age groups?
Among those who have COVID, mortality rate among the elderly with COVID is very high: 10.5% for those who are 80 or older, and 6.2% for those who are between 70-79.
Again, this is the case under a very aggressive trace-test-isolate strategy, but with no nation wide lock down. As of 2020-03-22, a total of 104 people with COVID have died, 1.2% among all COVID cases. These rates - overall as well as by age group - are lower than mortality rates in China.
There are news articles about extremely over-burdened health systems especially in Daegu. I’ve read a few mortality case on the newspaper while he/she was waiting for hospital admission, and patients from Daegu and a surrounding province being transferred to other less-affected provinces. However, my impression (as a public health trained reader) is that most severe cases do receive treatment at hospitals. I’m looking for more systematic data on health systems’ capacity and response.
Q 3. What age groups are affected?
For this question, let’s look at the total cumulative number of confirmed cases since the outbreak per 100,000 population by age group, not the absolute number. Also, keep in your mind, this is what we see under a very aggressive trace-test-isolate strategy (see this and this). Finally, KCDC releases the number by 10-year age group, and I’m following that categorization.
- Incidence rate is substantially high in the 20s: 36 people have been infected per 100,000 population in their 20s. At least partially, this is reflection of a very concentrated epidemic in Daegu related to a church, and the age pattern among the church attendants. So this age pattern may not be relevant for more generalized pandemic situation.
- Incidence rate among those under 20 is low. It may indicate either children are less susceptible, and/or - more importantly - they have been protected at home since all Korean schools have been in long winter break (typically over several weeks) or under temporary closure since the end of December, 2019.
Q 2. How fast has it been spreading?
For this question, let’s focus on the number of new cases by day. For about a month, only 30 cases were confirmed - mostly in/near Seoul. However, starting from the case No. 31 (a super transmitter who was confirmed on February 18), the number of new cases exponentially increased - primarily in Daegu and a region surrounding it but throughout the country. For 10 days, more than 400 new cases were confirmed everyday, with a peak of 909 new cases on February 29. More recently, the number of new cases started to decrease (see below). For the first time since February 22, the number of new cases is below 100 for two days in a row! Still, as of 2020-03-22, a total of 8897 people have been infected.
(Source: KCDC’s daily press release on 2020-03-22)In Daegu, where about three quarters of the cases are concentrated, the daily number of new cases has decreased clearly. 
(Source: Figure from KCDC’s daily press release, “Updates on COVID-19 in Korea (as of 19 March)”)
But, COVID can and does continue to spike up. In Seoul, there was a peak around the same time with the sharp epidemic in Daegu, followed by several days with much lower number of or no new cases. But, there seems to be a specific call-center related epidemic, as shown in the sudden increases in the number of new cases around March 11th.
(Source: Figure from KCDC’s daily press release, “Updates on COVID-19 in Korea (as of 19 March)”)
Q 1. When did it start?
On January 20, 2020, there was the first laboratory confirmed COVID case.
More questions and data coming soon, as I continue digging the awesome KCDC website…
See GitHub for data, code, and more information.
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